Following that definition, the convention defines chemical weapons as “(t) oxic chemicals and their precursors, except where intended for purposes not prohibited under this Convention, as long as the types and quantities are consistent with such purposes”.

Tamzek asserts that the mineral uraninite, present on the early Earth, cannot form under “significant exposure to oxygen”, however a recent publication from the Nasa Astrobiology Institute stated that its P.I. had observed the, “survival of uraninite … under an oxic atmosphere” and instability of uraninite under an oxygen-poor atmosphere, which was said to be “supporting … evidence for … an oxic Archaean atmosphere.”

Given that red beds–supposedly evidence of an oxic atmosphere, have been found contemporary with banded iron formations, it seems difficult to determine if the atmosphere strongly affects either of their formation, it is likely that neither are good indicators of atmospheric composition.